Electric relay.



H. DE F. ARNOLD.

ELECTRIC RELAY.

APPLICATION FILED MAY 10,1914.

1,1 14,845. Patented Oct. 27, 1914.

Wflv Ham/0 0 Amati UNITED STATES PATENT OFFICE.

HAROLD DE FOREST ARNOLD, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

ELECTRIC RELAY.

Specification of Letters Patent.

Patented Oct. 27, 1914.

To all whom it may concern:

Be it known that I, I-IARoLn Dn Fonns'r ARNOLD, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electric Relays, of which the following is a full, clear, concise, and exact description.

This invention relates to devices for amplifying feeble impulses of electrical energy, and more particularly to the audion as a repeater. 1

It has been found in the usual audion struc ture that when energies of considerable ma gnitude, such, for instance, as are encountered in ordinary telephone systems, are impressed upon the input circuit of the audion, a blue haze appears in the bulb of the audion. This blue haze may be produced in the bulb either by raising the potential. of the battery in the output circuit of the audion to an excessive value, or it may be produced by an increase in potential beyond a certain value between the grid and the filament. When the blue haze ispresent, the audion becomes inert and ceases to function as an amplifier. For instance, when used as a telephone relay, the transmission ceases almost entirely when the blue haze appears. It has been found experimentally that the establishment of the condition of discharge described above as the blue haze may be prevented by placing, in series with the battery, a balancing resistance of such high value that the increase in current which would normally take place when the condition in the bulb corresponding to the blue haze exists, results in such an increase in fall of potential across the resistance as to render the maintenance of the condition corresponding to blue haze impossible.

In the accompanying drawing,Figure 1 is a diagram illustrating one embodimentof the invention; and Figs. 2 and 3 are diagrams illustrating slight modifications of the system.

Like reference characters refer to like parts throughout the several views.

In said figures, the evacuated vessel 1 is provided as usual with a heated filament 2, a" grid 3 and a plate 4:. This device is well known in the art and is termed an audion. The input circuit of the audion includes the secondary coil of a transformer 5, the grid 3 and the filament-2. The output circuit of the audion includes the plate l, the primary coil of a transformer (3, the filament 2 and the battery 7. In accordance with this invention, there is included in this output circuit a balancing resistance 8. In Fig. 1, the resistance 8 is shown as connected in series with the primary winding of the transformer 6, a condenser 9 being placed in shunt of said resistance in order to permit the passage of fluctuating current.

In Fig. 2 an impedance coil 10 is placed in a bridge of the output circuit, the condensers 12, 12 being provided to prevent the passage-of direct current from the battery 7 while at the same time pern'litting the passage of fluctuating current.

In Fig. 3 the balancing resistance 8 is placed in series with the impedance 10 in a bridge of the output circuit.

The input circuit of the audion is inductively connected with the incoming line by the transformer 5, and the output circuit of the audion is inductively connected with the outgoing line by the transformer G. The filament 2 is connected to the opposite poles of a battery 11 in order to maintain said filament in a state of incandescence.

that is claimed is:

In an electric relay, the combination with an audion having an input and an output circuit, said output circuit including asource of direct current, of a balancing resistance in the output circuit in series with said source of direct current andv a condenser in shunt of said resistance, said balancing resistance being of such high value that the increase of current which normally takes place when a blue haze exists in the bulb of the audion, results in such an increase in fall of potential across said resistance as to prevent the maintenance of said blue haze.

In witness whereof, I hereunto subscribe my name this 14 day of May A. D., 1914.

.HAROLD DE FOREST ARNOLD.

Witnesses:

KATHERINE L. STAHL, ELLA EDLER. 

